I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transmitting data in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, broadcast, messaging, etc. These systems may be multiple-access systems capable of supporting communication for multiple users by sharing the available system resources, e.g., bandwidth and transmit power. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal FDMA (OFDMA) systems.
A wireless multiple-access system includes Node Bs (or base stations) that can communicate with user equipments (UEs). Each UE may communicate with one or more Node Bs via transmissions on the downlink and uplink. The downlink (or forward link) refers to the communication link from the Node Bs to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the Node Bs.
A wireless multiple-access system may support multiple-input multiple-output (MIMO) transmission on the downlink and/or uplink. On the downlink, a Node B may send a MIMO transmission from multiple (T) transmit antennas at the Node B to multiple (R) receive antennas at one or more UEs. A MIMO channel formed by the T transmit and R receive antennas may be decomposed into C spatial channels, where C≦min {R, R}. Each of the C spatial channels corresponds to a dimension. Improved performance (e.g., higher throughput and/or greater reliability) may be achieved by exploiting the additional dimensionalities created by the multiple transmit and receive antennas.
There is therefore a need in the art for techniques to efficiently support MIMO transmission in a wireless multiple-access system.